It has nothing to do with punishing other countries, although that just may be a side benefit. There's money to be made in uncertainty. Remember the suddent rise in the stock market following the rumor that originated on X:
"The false posts may have originated from a real Fox News interview with National Economic Council Director Kevin Hassett at around 8:30 a.m. ET. Hassett was asked whether President Donald Trump would “consider a 90-day pause in tariffs,” and he replied in part: “The president is (going to) decide what the president is (going to) decide.” (https://www.cnn.com/2025/04/07/media/fake-news-x-post-caused-market-whiplash/index.html)
That, I suspect was a mere test -- albeit profitable for anyone who knew about the rumor ahead of time -- to see what the effect of a change in tariff policy --or even a pretend one -- would have on the market.
Anyone (like the Trump family and other insiders) who knew what the president was going to announce stood to make billions thanks to the volitility and over-reaction of the market to anything related to tariffs.
Hedge funds short and then buy and the huge swings in the market afford literally billions in profits. Trump's flip-flops are bad for business because it inhibits planning, but it's wonderful for insiders, especially the Trump family who will know the timing of the flips and flops. In the meantime Trump can grandstand that tariffs are in the best interest of the country. Whether they are or not is completely irrelevant to his get-rich-quick strategy by manipulating the market.
Expect more flips and flops and for the billionaires and Trump friends to become trillionaires while the rest of us poor schmucks just sit back and wonder what the hell happened.
Follow the money.